1. Field of the Invention
The present invention relates to dyeing of cellulosic fabric. More particularly, the present invention relates to compositions for uniformly providing, preferably by spraying, a dye on both surfaces or sides of a cellulosic fabric. In a less preferred embodiment, the present invention relates to compositions having a mixture of reactive dyes, which compositions provide a uniform color on both sides of a cellulosic greige or scoured or bleached fabric, by a spray application of the composition to the fabric.
2. Description of Related Art
Today, fabrics are made from a wide-variety of natural fibers, such as cotton, synthetic fibers, or any combination thereof. The basic fabric is a greige fabric that is needed to be dyed in order to provide the desired color to the resultant fabric and/or garment. Many compositions and methods have been proposed for dyeing fabrics, however all have proven costly in material cost, as well as time.
One method, commonly referred to as yarn dyeing, involves dyeing individual fibers or yarns prior to these fibers being sewn or knitted into a fabric. One problem associated with this method is inventory control of the yarns and associated garments. For example, yarn dyeing requires the garment manufacturer to maintain a supply of the various colored yarns used in its products, which inventory increases cost.
Another dyeing method is commonly referred to as bulk dyeing. In bulk dyeing, un-dyed fibers or yarns are knitted or woven into a raw or un-dyed fabric. The raw fabric is subsequently scoured or bleached and then dyed. The dyed fabric is then used to make the desired product, such as a garment.
Some common bulk dyeing methods include vat dyeing, beam dyeing, jet dyeing, and bath dyeing. Vat dyeing typically consists of immersing a piece of fabric in a vat of liquid dye. Beam dyeing involves winding a length of fabric about a perforated beam. The beam is then placed in a vessel where liquid dye is pumped into the center of the beam, out of the perforations, and through the fabric. Jet dyeing involves placing the fabric in a high-pressure, high-temperature kettle of liquid dye. Bath dyeing involves immersing the fabric in a bath of dye, which is contained in a rotating drum.
One problem associated with such bulk dyeing methods relates to the fabric that is cut away or removed during manufacture of the fabric into the desired garment. The fabric that is cut away has been dyed and, thus, includes the cost of the dye. This can lead to an increased cost of goods for garments made from bulk dyed fabrics. Another problem with bulk dyeing methods relates to the large amounts of water required during processing, which can increase cost of goods for such bulk dyed fabrics, as well as having an adverse effect on the environment and an erosion of resources.
A more significant problem with bulk dyed fabrics in the manufacture of garments is the unpredictability of consumer color preferences. In the garment industry, change in the consumer's preference for one color over another color can lead to an overstock of the undesired colored garments and a back order situation of the desired colored garments. Thus, garments made from bulk dyed fabrics have not proven flexible enough to meet increasing and changing consumer demands.
Further methods of dyeing fabrics involve printing a dye onto a surface of a fabric. This method is commonly used to apply a decorative pattern on the surface of the fabric. Such printing methods include screen-printing and inkjet printing. While these methods have proven useful in quickly changing from one decorative pattern to another, they have not proven useful in bulk dyeing of fabrics or completed garments.
Perhaps, one of the cost effective methods of dyeing a fabric is spray dyeing. Spray dyeing, as used herein, includes conventional spraying as well as atomization and electrostatic applications. However, a problem with spray dyeing is to provide a uniform dye on both sides of the garment. Normally, to attempt to achieve such uniformity requires spray dyeing on both sides of the fabric or garment in a very controlled environment. Also, the fabric or garment must remain in a taut position in order to provide penetration into the fabric or garment yet not have any garment area that is covered or unavailable for receipt of the spray. This is difficult to achieve, let alone in a cost effective manner, especially if both sides of the garment are to be spray dyed.
Accordingly, there is a need for a composition and resultant method of dyeing cellulosic, especially greige or scoured or bleached, fabrics that provide uniform color on both sides of the fabric. It is particularly important to provide such a composition that can dye cotton to any desired color in one basic spray step or operation without the need of a controlled environment and without the problems noted above for positioning the fabric or garment, yet with good dye penetration into the fabric or garment.